1. Field of the Invention
The present invention relates to an optical module which is sealed by mold material.
2. Related Background Art
In recent years, packaging techniques for semiconductor integrated circuits have made great progress and various kinds of electronic parts are packaged with high density. Therefore, it is an important subject to reduce noises caused by the adjacent electronic parts. In general, a noise source is an atmospheric electric wave generated by the adjacent electronic parts, a noise of the power source through GND/power lines or others. In particular, countermeasure for the noises is important for an optical module which converts a feeble optical signal into an electric signal.
In the conventional optical modules, for certain electronic parts installed inside, a metal shielding board was installed or instead of the electronic parts, other circuit parts for reducing noise were mounted.
However, in such shielding structure in which the electronic parts were shielded, a shielding member larger than the electronic parts was installed, and in particular, in a case that shielding was required on a same substrate, a region occupied by the shielding member on the substrate was substantially large. This hindered the advance of miniaturizing a module.
For the electronic parts, an additional process of installing the shielding member was required, which caused both an increase of the number of processes of building the optical module and a fall of the productive efficiency.
Further, there was a practical problem that in the resin molding type products, the shielding member was broken by the stress when resin was poured.